aggressiveCows

    #include <bits/stdc++.h>
    using namespace std;
    bool isPossible(int a[], int n, int cows, int minDist) {
        int cntCows = 1; 
        int lastPlacedCow = a[0];
        for(int i = 1;i<n;i++) {
            if(a[i] - lastPlacedCow >= minDist) {
                cntCows++;
                lastPlacedCow = a[i]; 
            }
        }
        if(cntCows >= cows) return true;
        return false; 
    }
    int main() {
    	int t;
    	cin >> t;
    	while(t--) {
    	    int n, cows;
    	    cin >> n >> cows;
    	    int a[n];
    	    for(int i = 0;i<n;i++) cin >> a[i]; 
    	    sort(a,a+n); 
    	    
    	    int low = 1, high = a[n-1] - a[0]; 
    	    
    	    while(low <= high) {
    	        int mid = (low + high) >> 1; 
    	        
    	        if(isPossible(a,n,cows,mid)) {
    	            low = mid + 1;
    	        }
    	        else {
    	            high = mid - 1; 
    	        }
    	    }
    	    cout << high << endl; 
    	}
    	return 0;
    }